Analysis of the genetic control of autoimmune disease and plasmacytoma induction in mice is currently following several approaches. Firstly to determine whether these phenomena involve the same genes that are associated with refractoriness to tolerance induction and secondly, possible relationship to other loci known to control immune responsiveness, i.e., the H-2 region and allotypes. Development of a series of allotype and histocompatible NZB and BALB/c mice is continuing. Analysis of surface markers on a series of mineral oil induced B cell lymphomas is being performed to investigate the thesis that these lymphomas may represent maturational arrest of distinct stages in B cell differentiation. BIBLIOGRAPHIC REFERENCES: Warner, N.L. Autoimmunity and the pathogenesis of plasma cell tumor induction in NZB inbred and hybrid mice. Immunogenetics 2, 1 (1975). Warner, N.L. and Anderson, R.E., Helper effect of normal and irradiated thymus cells on transferred immunoglobulin production. Nature 254, 604 (1975).